| M | F | N | P | |
| N | -er | -e | -es | -en |
| A | -en | -e | -es | -en |
| G | -en | -en | -en | -en |
| D | -en | -en | -en | -en |
You may wonder why a plural is shown. That's because the mixed declension is used after kein and the possesive pronouns mein, dein, sein and so on. It is also used after manch ein, solch ein, welch ein, ein solcher.
The 3 positions in the table that differ from the weak endings all follow determiners which have no ending e.g. ein, mein, kein. Where the adjective has -en as ending then the determiner has its own ending e.g. the masculine accusative, genitive and dative - meinen alten Freund, meines alten Freundes, meinem alten Freund.
Again it is really worth working through some exercises to practise these. You find some useful exercise here
